Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser EarthX Batteries Garmin G3X Touch
Results 1 to 6 of 6

Thread: Question for all the wing folders

  1. #1
    Senior Member
    Join Date
    Apr 2010
    Location
    Bryan, Texas
    Posts
    558

    Default Question for all the wing folders

    I mounted the wings on my KF 4 the other day for a test fit. Since this is a restore after a crash and semi minor repairs to the wings, I have left everything as it was set up originally. My questions is....when unfolding the wings and hooking the front spar to the carry through tube, I have to push up on the lead edge a little to get the spar to go over the tube. When I go to fold, the lead edge drops down as I start to swing the wing back. We're talking about an inch maybe and it's both wings. The other thing I noticed is when the the wings are folded, I can push up and down on the lead edge and I notice that the end root rib really flexes. Probably due the material that was removed in order to run the fuel line. I can see the spars moving slightly around the fuel tank as I twist the wing. Is this stuff normal? Do I need to reinforce the end rib? I know the tanks are siliconed in place so there is going to be some flex but I don't know how much. Once pinned in place everything sures up but from some of the vidoes I have seen, It looks like when unfolding the wings, they line right up with no manipulation and drop the pin in.

    Thanks

  2. #2
    Senior Member t j's Avatar
    Join Date
    Oct 2009
    Location
    Ellensburg, WA
    Posts
    861

    Default Re: Question for all the wing folders

    Jerry, I built and rigged, and fold my model 4's wings every flight. This is my opinion, you should get more.

    I would want to see whats going on under the cover. While I was rigging my wings I got everything perfect except one front spar would drop about 1/4 inch when swung away from the fuselage lug. I called the factory and the guy I talked to said that wasn't too bad. Consider this. The rigging is checked with the wings spread. If the front spar drops when released then something is flexing to get to that correctly rigged condition. I eventually got it to where it was rigged to a nat's eyebrow and neither front spar drops when swung away from the lug. Flys hands off straight and level. A very slight left rudder needed.

    The RTV used to secure the fuel tanks to the spars is very tenacious. I removed one of my tanks once and there is no way you could budge or get any flex between the spars and tank before the RTV was cut through.

    There should be just a little flex at the root rib when the wings are folded. Its hard to describe. The best way to get a feel for it would be to find another plane to feel how ridged they are with your own hands. Excessive flexing there could be from several causes. Rib to spar adhesive has come loose, crack in fuselage spar lug weld, on and on.

    I know this isn't what you wanted to hear but it is just one opinion so far.
    Tom Jones
    Classic 4 builder

  3. #3

    Join Date
    May 2009
    Location
    FRANCE
    Posts
    174

    Default Re: Question for all the wing folders

    Got exactly the same on my KF2 but don't know if it's normal....

    All i can say is i'm alive after about 70 hours in it

  4. #4
    Senior Member
    Join Date
    Apr 2010
    Location
    Bryan, Texas
    Posts
    558

    Default Re: Question for all the wing folders

    I started thinking about this wing folding thing. Since this plane was crashed, not real hard but nonetheless, crashed and rebuilt including structural fuselage tubing, I started thinking that the wings were rigged for the fuselage before repairs. This means they will probably need to be re-rigged since the fuselage is most likely slightly different from the repairs. This morning I checked a couple things quickly before I had to start real work, and will do the official checks with levels later. I noticed with the left wing pinned in place there is a noticeable dip in the fabric near the edge of the fuel tank. This tells me that I am really putting a twist in the wing to get the front spar lined up and pinned. I decided to adjust the lift struts slightly to see if this made any difference. I turned the rear one 2 turns shorter and like magic, the front spar was within a 1/4 inch of being perfectly lined up. I put another turn on in and it lines up and goes in with no effort. I think I might still reinforce the end rib where the fuel line cut out was made. I did notice that when I push up and down on the leading edge flexing the rib, I make the fabric tauntness change. Just sitting in it's normal position the fabric is good and smooth and with the wing pinned in place it looks good so I feel pretty confident that there is nothing going on with fuel tank coming loose or aything. I am going to re-rig both wings later to make sure they are the same. i.e. twist, washout etc.

  5. #5

    Join Date
    Jun 2009
    Location
    Pittsgrove, Southern New Jersey
    Posts
    113

    Default Re: Question for all the wing folders

    Since we are talking wings here, I have a question related to this as well. It might be a related problem you are having as well. My model IV starboard wing, the forward root pin goes in nicely. The port pin is off somewhat. The previous owner used to hammer it in. Ah...I don't hammer things on my equipment. My question is this: Would it be ok to ream out the hold a few thousands to make the pin slide in and out better? I see there is a bit of misalignment between the spar tabs and the root tube on the port side.Thanks for you help-Tom(Lion8)

  6. #6
    Senior Member t j's Avatar
    Join Date
    Oct 2009
    Location
    Ellensburg, WA
    Posts
    861

    Default Re: Question for all the wing folders

    I would use a small rat tail or round file and carefully remove only the portion of the spar attach reinforcement fitting that is misaligned with the root tube. file just a little , try the pin, file a little more, try it again...until the pin goes in without the hammer.

    My wing pins get a little hard to install if I don't put a little white lithium grease on them once in a while.
    Tom Jones
    Classic 4 builder

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •